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Slide gate operator

All-O-Matic SL-100 Repair in Dallas–Fort Worth

We repair All-O-Matic SL-100 slide operators — the original SL-100AC, the foot-pedal SL-100FP AC and the SL-100DC PRO. The call we get most is a gate that travels a few feet, stops and reverses, which on this model is the reversing sensor reacting to load, not a clutch.

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  • Licensed & Insured
  • 16+ Years Experience
  • Open 24/7
  • Residential & Commercial

Is this a All-O-Matic SL-100?

The SL-100 name covers three operators. The original SL-100AC is released by switching the power off and pushing the gate (a crank is also supplied), and All-O-Matic now lists it as discontinued. The SL-100FP AC adds a mechanical foot-pedal release. The SL-100DC PRO keeps the pedal but swaps the AC motor for a 24-volt brushless one with two batteries built in. They share a footprint and a chain, but the boards, gearboxes and faults differ, so knowing which one is on your gate saves a wasted trip.

Start with the label on the chassis. If it is faded, look at the release: no pedal means the regular SL-100AC, a pedal means FP AC or DC PRO, and a pair of 12-volt batteries plus a board with a small LCD menu means the DC PRO. If the unit has a separate limit box and a large clutch nut on the gearbox, it is not an SL-100 at all — that is the heavier SL-150.

  • Chassis label reading SL-100AC, SL-100 ACFP, SL-100FP AC or SL-100DC PRO
  • A #41 roller chain along the gate, bolted to a bracket at each end
  • Two limit nuts on a threaded shaft beside the gearbox, held by a notched lock plate
  • A foot pedal on the chassis (FP AC and DC PRO) — or no pedal on the regular SL-100AC
  • Two 7Ah 12-volt batteries inside the housing (DC PRO only)
  • No clutch nut on the gearbox and no separate limit box

Also labelled: SL-100AC, SL-100FP AC, SL-100 ACFP, SL-100FPAC, SL-100DC PRO, SL-100DCFP

SL-100 at a glance

Motor (AC versions)
1/2 HP, 120 VAC single phase
Motor (DC PRO)
24 VDC brushless, 1/2 HP
Max gate weight
1,000 lbs (SL-100AC, SL-100FP AC); 2,000 lbs (SL-100DC PRO)
Max gate length
37 ft (SL-100AC); 50 ft (SL-100DC PRO)
Gate speed
12 in per second
Duty cycle
Continuous
Gearbox
10:1 (SL-100AC); 20:1 with internal disconnect (FP AC and DC PRO)
Belt
4L-300 (AX28) on SL-100AC; 4L-260 (AX24) on FP AC and DC PRO
Chain
41NP, 20 ft included
Emergency release
Push open with power off (SL-100AC); mechanical foot pedal (FP AC, DC PRO)
Battery backup (DC PRO)
Integrated, two 7Ah 12 VDC batteries; about 80 cycles on a 1,000 lb gate
Control board
AC control board ACPCB-UL (AC versions); BLDC-ULPCB1 (DC PRO)
UL 325
Listed by All-O-Matic as UL 325 2018 compliant
Temperature range
−40° to 160°

From All-O-Matic’s published documentation. Your unit’s label and manual take precedence.

What your SL-100 is doing, and what usually causes it

  • The gate moves a few feet, stops and goes back

    Usually: The ERD sensing extra load — flat-spotted wheels, a dirty or bent track, a post that has moved — or a sensitivity pot and jumper that do not match the SL-100’s single-capacitor motor.

    What we do: Release the operator and roll the gate its full length by hand. If it binds, we fix the gate first. Only then do we check the jumper position, set the pots and confirm the gate still reverses on an obstruction.

  • It stops a little short of closed, or overshoots where it used to stop

    Usually: A limit nut that has moved a notch or two, a lock plate left out of its locked position, or a gate that now sits differently on worn wheels so the old stop points are in the wrong place.

    What we do: We check the gate’s position on its track, reset the nuts a notch at a time (about half an inch each), lock the plate and run several full cycles.

  • The motor hums but the gate doesn’t move

    Usually: All-O-Matic’s AC troubleshooting points to both open and close triacs on the board when the motor hums without moving. A failed motor capacitor, a slipping belt or a seized gate can sound similar.

    What we do: We rule out the gate and belt by hand, test the capacitor, then check the board’s outputs before condemning anything.

  • After a power cut the gate started moving on its own and ignored the limits

    Usually: All-O-Matic identifies this as a failed open or close triac on the AC board.

    What we do: We confirm the fault, then give you the choice of sending the board to All-O-Matic’s repair service or fitting a replacement, with the cost and wait for each.

  • It only moves while someone holds the button

    Usually: The board is in constant-pressure mode because a monitored photo-eye or edge is missing, misaligned or faulty, or the firmware mode does not match the wiring.

    What we do: We read the MON-FAULT blink count, test each monitored device and correct the wiring or alignment — we do not jumper out safety inputs.

  • Nothing runs after someone used the foot pedal

    Usually: On the FP AC and DC PRO the pedal has a kill switch. If the pedal is not fully up, the operator will not run; the STOP CMD LED (AC) or FP_DISABLE LED (DC PRO) shows it.

    What we do: We reset the pedal, check that the gearbox disconnect has re-engaged and adjust the pedal switch if it is not releasing.

  • The DC PRO stopped and the ALARM light is on

    Usually: Shutdown after the ERD tripped twice before the gate fully closed. The MODE LED may also be blinking: once for a motor sensor feedback fault, twice for motor overload, three times for a jammed gate.

    What we do: We find what the gate hit or dragged on, clear it, reset the board and test the reversing force in both directions.

SL-100 down? Tell us what it is doing — we will tell you what it needs.

(214) 735-4314

How the SL-100 works — and what that means for repair

Belt to gearbox to chain

The motor drives the gearbox through a V-belt, and the gearbox sprocket pulls a #41 chain fixed to the gate. On the regular SL-100AC the gearbox ratio is 10:1 with a 4L-300 (AX28) belt. The FP AC and DC PRO use a 20:1 gearbox with an internal disconnect — the part the foot pedal works — and a shorter 4L-260 (AX24) belt. All versions are rated at 12 inches per second.

That belt matters for diagnosis. A glazed or loose belt lets the motor spin while the gate hesitates, and it is a small part next to a gearbox. On the FP and DC PRO versions a disconnect that has not fully re-engaged after someone used the pedal produces a similar "motor runs, gate barely moves" complaint.

No slip clutch — the board does the reversing

All-O-Matic’s specifications list an internal clutch for the SL-150, not for any SL-100 version. On the SL-100, obstruction protection comes from the control board’s Electronic Reversing Device (ERD), which reverses the gate when motor effort rises past its sensitivity setting.

So when an SL-100 stops and reverses mid-travel, nothing is slipping. The ERD is reacting to load: a genuine obstruction, a gate that has become hard to roll, or a sensitivity setting that does not match the motor. All-O-Matic’s own tip for an ERD that keeps tripping with the pot fully clockwise is to check that the gate opens and closes easily by hand first, then confirm the ERD jumper position. On the 2022 AC board the chart puts the SL-100 (1/2 HP, one capacitor) on pins 5–6.

Limit nuts and the lock plate

Travel is set by two limit nuts on a threaded shaft. You push the lock plate down, turn a nut toward its switch to shorten travel or away to lengthen it, and each notch moves the stop point roughly half an inch. The plate then has to go back into its locked position — the manual is blunt that the gate will not hold its limits otherwise.

An unseated plate is behind a lot of SL-100 calls where the gate slowly starts stopping short or running long over a few weeks. It is an adjustment, not a part.

Which safety firmware your AC board is running

Current AC boards support monitored entrapment devices, and the firmware mode has to match how the photo-eyes or edges are wired. Press and release RESET and count the MON-FAULT blinks: one means pre-UL (no monitored device required), two means UL-2016 (one monitored device for closing), three means UL-2018 (one each for opening and closing).

If a required device is missing, unplugged or faulty, the board will only run the gate with a constant-pressure control. That is why an SL-100 that "only moves while I hold the button" often traces back to a photo-eye that was swapped or knocked out of alignment.

SL-100 parts we repair, adjust or replace

A failed part is not a failed operator. These are the components that actually wear or fail on the SL-100, and what we do about each.

  • AC control board (ACPCB-UL)

    Repaired

    Runs the motor through triacs, sets ERD sensitivity and handles the monitored safety inputs.

    Signs it has failed: Humming without movement, running without a command, a 24VDC overload light, or no response at all.

  • Limit nuts, limit shaft and lock plate

    Adjusted

    Set where the gate stops at each end of travel.

    Signs it has failed: Stop points drifting over weeks; a gate that will not hold a fresh adjustment.

  • Limit switches

    Part replaced

    Tell the board the gate has reached a stop point when a nut presses them.

    Signs it has failed: Gate runs into the end post, or stops dead short even with the nuts set correctly.

  • V-belt (4L-300 or 4L-260)

    Part replaced

    Carries power from the motor pulley to the gearbox.

    Signs it has failed: Squeal on start, motor spinning while the gate hesitates, glazed or cracked sides.

  • Gearbox and internal disconnect (FP AC, DC PRO)

    Serviced

    Reduces motor speed to drive the chain sprocket; the disconnect frees the gate for manual use.

    Signs it has failed: Grinding, play in the output sprocket, or the gate staying free after the pedal is lifted.

  • Motor capacitor (AC versions)

    Part replaced

    Gives the single-phase motor its starting and running torque.

    Signs it has failed: Slow or failed starts, humming, a motor that runs hot.

  • #41 chain and gate brackets

    Adjusted

    Transfers drive to the gate.

    Signs it has failed: Slack slapping the housing, rust, a chain riding up on the sprocket.

  • Batteries (DC PRO)

    Part replaced

    Keep the gate cycling through a power outage.

    Signs it has failed: LOW-BATTERY LED on, or the gate stranded open or closed during an outage.

Repair or replace your SL-100? The honest answer

Most SL-100 faults are adjustments or single parts: limit nuts, a belt, a capacitor, a photo-eye or a board. Replacement makes sense when the gate has outgrown the operator or the gearbox itself is worn out, and on a regular SL-100AC it is worth weighing that against the fact All-O-Matic no longer builds that version.

Repair it when

  • Stall-and-reverse that goes away once the gate rolls freely by hand
  • Limits drifting because the lock plate or a nut has moved
  • A board with a failed triac — All-O-Matic repairs defective boards, including out-of-warranty ones, provided parts are still available and there is no surge or water damage
  • Belt, capacitor, limit switch or battery failures

Replace or upgrade when

  • The gate weighs more than 1,000 lbs on an AC version — the SL-100DC PRO is rated to 2,000 lbs and the SL-150 class goes higher
  • The gearbox on a regular SL-100AC is worn and a replacement is not practical; All-O-Matic names the SL-100DC PRO as the successor
  • You need battery backup on an AC unit that has no provision for it
Call Now — (214) 735-4314Request a Free Estimate for All-O-Matic SL-100 repair

Case studies

All-O-Matic repairs we have documented

Other All-O-Matic operators, written up in full — the same diagnose-first approach we take on a SL-100.

All case studies

Our All-O-Matic work

Photographs from our own All-O-Matic jobs — a mix of models, not all of them the SL-100. None of it is stock.

  • An All-O-Matic slide gate operator housing beside a driveway gate track
  • The chain drive and sprocket of an All-O-Matic slide operator with the cover removed
  • An All-O-Matic operator opened for inspection, showing the limit switch cams and drive assembly
  • A technician's multimeter resting on the control board of an opened gate operator during electrical testing

How we diagnose and repair a SL-100

  1. Identify the version

    SL-100AC, FP AC or DC PRO — the label, the release and the batteries tell us which board, gearbox and belt we are dealing with.

  2. Release and roll the gate

    We free the gate and push it the full length of the track. Any tight spot here explains most reversing complaints before we open the housing.

  3. Read the board

    We note which LEDs are lit, count the MON-FAULT blinks on AC boards or the MODE blinks on DC PRO boards, and check the ERD jumper position.

  4. Check the drive and limits

    Belt tension and condition, chain slack, the pedal disconnect, and the limit nuts and lock plate.

  5. Test electrically

    Capacitor, limit switches, board outputs and every monitored safety device, one at a time.

  6. Quote, repair and prove it

    You get the price before work starts. After the repair we run full cycles and confirm the gate reverses on an obstruction in both directions.

All-O-Matic warranty on the SL-100

All-O-Matic warrants the SL-100 for seven years in residential installations and five years in commercial installations against defects in circuitry, motor, gearbox and workmanship, from the date of purchase to the original owner — provided the registration card is mailed within 30 days. Unregistered units receive one year on parts.

  • Labor for dealer service is the owner’s responsibility under All-O-Matic’s written warranty, and warranty items are returned to the manufacturer at the owner’s expense.
  • All-O-Matic advance-replaces items within the first two years after troubleshooting with its tech support from the job site; after two years warranty items are repair-and-return.
  • Board repairs are excluded where there is power-surge or water damage.
  • The terms are printed in the warranty section of the SL-100 manual and on each allomatic.net product page.

Our warranty on the repair

Every repair is backed by a clear written warranty. No hidden terms and no confusing fine print: what is covered is explained before we begin, and it is separate from whatever All-O-Matic covers on the operator itself.

What our warranty covers

The SL-100 in Dallas–Fort Worth conditions

Storm surges and the board-repair exclusion

North Texas spring storms bring lightning, and a surge is the one kind of board failure All-O-Matic’s free board-repair policy does not cover. If your SL-100 died during a storm, expect the board to need replacing rather than repairing, and ask whether the operator has a proper ground — it is the cheapest protection the next board will get.

Clay soil makes the ERD look faulty

Expansive clay moves slide-gate posts and pads as it dries in summer and swells after rain. A track that drops or a receiving post that leans makes the gate harder to roll, and the SL-100’s reversing sensor reads that extra effort as an obstruction. Turning the sensitivity down hides it until the next dry spell; re-levelling the track fixes it.

Heat and DC PRO batteries

All-O-Matic rates the DC PRO to 160°, but the batteries inside a sun-baked housing age faster in a Dallas summer than anywhere cooler. If the LOW-BATTERY light comes on or outage cycles fall well short of what the gate used to manage, test the batteries before suspecting the board.

All-O-Matic SL-100 repair across DFW & Surrounding Areas

Customer testimonials

Real Customers. Real Repairs. Watch Our Customers Tell Their Stories.

Real Shield Gate Repair customers describing the job in their own words, All-O-Matic jobs first.

Watch every customer video

All-O-Matic SL-100 repair questions

Does the All-O-Matic SL-100 have a clutch I can tighten?

No. All-O-Matic lists an internal clutch on the SL-150, not the SL-100. The SL-100 reverses through the board’s ERD, so a stall-and-reverse means it is sensing load. The fix is finding what makes the gate hard to move, not turning sensitivity down until it stops reacting.

How do I tell an SL-100AC from an SL-100FP AC or DC PRO?

Check the chassis label. Without one, look at the release: no foot pedal is the regular SL-100AC, a pedal is FP AC or DC PRO, and two 12-volt batteries in the housing mean DC PRO.

Is the SL-100 still made?

The original SL-100AC is listed as discontinued, with the SL-100DC PRO named as its successor. The SL-100FP AC and SL-100DC PRO are current on All-O-Matic’s site.

I adjusted my SL-100 limits and they won’t hold. Why?

Almost always the lock plate. After turning the limit nuts the plate has to drop back into its locked position, or the nuts turn with the shaft and the stop point wanders.

Can a failed SL-100 board be repaired instead of replaced?

Often. All-O-Matic repairs defective boards, including out-of-warranty ones, when components are still available and the board has no surge or water damage. We will tell you whether yours qualifies and how long the turnaround is compared with a replacement.

Can my SL-100 move a heavier gate if I adjust it?

Not safely. The AC versions are rated to 1,000 lbs and the DC PRO to 2,000 lbs. Beyond that the answer is a larger operator, not a less sensitive reversing setting.

Request a free estimate for your SL-100

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Or call (214) 735-4314 — someone always answers.

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